To you it's crazy that the person in customer service wants to give you a correct answer without having to worry about mistakingly not carrying a digit and then customers throwing a hissie fit because "well you said 7531 not 8531 and you're a representative of the company so I'm going to pick and choose to pay the lower number rather than what I know I owe, get shit on by your manager for it, I don't care"? Idk man, to me it just sounds like a smart idea - leave no room for error, let the machine be responsible for if you're tired and can't mental math for a second. It even shows you the numbers you added, you can double and triple check the result within seconds, no need to go out and prove you attended elementary school.